U.S. patent number 8,228,182 [Application Number 12/483,039] was granted by the patent office on 2012-07-24 for self-testing notification appliance.
This patent grant is currently assigned to SimplexGrinnell LP. Invention is credited to Anthony J. Capowski, Michael A. Furtado, Todd F. Orsini.
United States Patent |
8,228,182 |
Orsini , et al. |
July 24, 2012 |
Self-testing notification appliance
Abstract
A self-testing notification appliance includes a notification
emitter, a verification circuit, and a controller. The notification
emitter is operable to output light or light and sound based on a
control signal. The verification circuit includes a notification
sensor to detect the light or light and sound and generate a
verification signal. The controller sends the control signal to the
notification emitter and receives information based on the
verification signal from the verification circuit. The self-testing
notification appliance may be part of a network including a fire
control panel and a plurality of additional self-testing
notification appliances. The self-testing notification appliances
may be assigned addresses on the network.
Inventors: |
Orsini; Todd F. (Sterling,
MA), Capowski; Anthony J. (Westford, MA), Furtado;
Michael A. (Shrewsbury, MA) |
Assignee: |
SimplexGrinnell LP
(Westminster, MA)
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Family
ID: |
43305939 |
Appl.
No.: |
12/483,039 |
Filed: |
June 11, 2009 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100315224 A1 |
Dec 16, 2010 |
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Current U.S.
Class: |
340/514; 315/133;
340/3.43; 340/538.15; 250/200; 340/507; 340/641; 315/134; 340/505;
250/206; 340/331 |
Current CPC
Class: |
G08B
29/126 (20130101) |
Current International
Class: |
G08B
29/00 (20060101); H05B 39/00 (20060101); G08B
5/00 (20060101) |
Field of
Search: |
;340/514 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO 2008/132475 |
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Nov 2008 |
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WO |
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Primary Examiner: Crosland; Donnie
Attorney, Agent or Firm: Brinks, Hofer, Gilson &
Lione
Claims
What is claimed is:
1. A self-testing notification appliance, comprising: a
notification emitter operable to output a visual fire alarm in
response to a control signal; a verification circuit including a
notification sensor configured to detect at least a part of the
visual fire alarm and configured to generate a verification signal;
and a controller operable to send the control signal to the
notification emitter and to receive test information based on the
verification signal.
2. The self-testing notification appliance of claim 1, wherein the
controller receives instructions to generate the control signal
from an external control panel.
3. The self-testing notification appliance of claim 1, wherein the
verification circuit further comprises a threshold detector
configured to compare the verification signal with a threshold
value and communicate a result of the comparison to the
controller.
4. The self-testing notification appliance of claim 3, wherein the
verification circuit further comprises a measurement circuit to
generate a digital representation of the verification signal and
communicate the digital representation as the test information to
the controller.
5. The self-testing notification appliance of claim 1, wherein the
visual fire alarm is a light, the appliance further comprising: a
reflector mounted between the notification emitter and the
verification circuit; and an opening located in the reflector to
allow the light to pass through the reflector and reach the
notification sensor.
6. The self-testing notification appliance of claim 1, wherein the
notification emitter comprises a strobe light or flashtube and the
notification sensor comprises a photodetector.
7. The self-testing notification appliance of claim 1, wherein the
notification emitter comprises a light emitting diode (LED) and the
notification sensor comprises a photodetector.
8. The self-testing notification appliance of claim 1, wherein the
controller is configured to adjust the brightness of the
notification emitter based on the verification signal.
9. The self-testing notification appliance of claim 1, wherein the
controller is configured to instruct the verification circuit to
detect the visual fire alarm for a selectable time period.
10. The self-testing notification appliance of claim 1, wherein the
notification appliance is addressable on a network in communication
with a fire control panel.
11. A method of testing a notification appliance including a
notification emitter, a verification circuit, and a controller, the
method comprising: emitting a visual fire alarm from the
notification emitter based on a control signal from the controller;
detecting at least a part of the visual fire alarm with a
notification sensor included in the verification circuit; and
sending a verification signal indicative of the detection to the
controller.
12. The method of claim 11, further comprising: sending a test
result indicative of the detection from the controller to an
external control panel; logging the test result and an address of
the notification appliance in a memory; and outputting the results
from the external control panel.
13. The method of claim 12, wherein the outputting comprises
printing the test result, displaying the test result, or sending an
electronically transmitted message including the test result.
14. The method of claim 11, further comprising: comparing the
verification signal to a threshold value.
15. The method of claim 11, wherein detecting the visual fire alarm
with the notification sensor further comprises: generating a
digital representation of the output of the notification sensor as
the verification signal.
16. The method of claim 11, wherein the notification emitter
comprises a strobe light or a flashtube and the notification sensor
comprises a photodetector.
17. The method of claim 11, wherein the controller is configured to
adjust the brightness of the notification emitter based on the
verification signal.
18. The method of claim 11, further comprising: assigning a network
address to the notification appliance.
19. A notification system including a fire alarm control panel and
a plurality of self-testing notification appliances, the
notification system comprising: a controller configured to send a
power signal and a control signal to a notification appliance of
the plurality of self-testing notification appliances; wherein each
of the plurality of self-testing notification appliances comprises:
a strobe configured to output an amount of light based on the
control signal; and a verification circuit including a photodiode
configured to detect the amount of light from the strobe based on
the control signal, the verification circuit configured to
interrupt the power signal if the amount of light from the strobe
is below a threshold.
20. The notification system of claim 19, wherein the controller is
configured to identify the interruption of the power signal as a
failure of the strobe.
21. The notification system of claim 20, wherein the controller is
configured to log the failure of the strobe in a memory.
22. The notification system of claim 20, wherein the fire alarm
control panel controller is further configured to print, display,
or email the failure.
23. The notification system of claim 19, wherein the fire alarm
control panel sends the control signal to the plurality of
self-testing notification appliances by way of a common
circuit.
24. A self-testing notification appliance comprising: a strobe
configured to receive a power signal from an external device and
output an amount of light based on a control signal received from
the external device; and a verification circuit including a
photodiode configured to detect the amount of light from the strobe
based on the control signal, the verification circuit configured to
interrupt the power signal if the amount of light from the strobe
is below a threshold.
Description
BACKGROUND
Most single family residences and apartments rely on individual
smoke detectors with built-in alarms that can be easily placed in
various rooms. Larger buildings, such as apartment or condominium
buildings, industrial plants, and schools often require more
complex, networked commercial fire alarm systems. These fire alarm
systems may include a controller that is centrally located and
communicates with numerous alarms and detectors positioned over a
large area. The alarm units provide light notification, sound
notification, or both to occupants in the vicinity of the alarm.
These systems are generally required to be tested periodically to
verify that the system is fully operational.
In the conventional commercial system shown in FIG. 1, a fire alarm
controller 113 communicates through communication line 109 with an
alarm 103. More alarms 103 may be located in other rooms of the
building or in other buildings located in the campus or
complex.
A testing procedure is typically used to assess whether or not the
alarms 103 and controller 113 are properly working. Conventionally,
the testing procedure involves at least two people. A first service
representative 101 is sent out into the building or complex with a
two-way radio 105. A second service representative 100 must stay
near the alarm controller 113, which is connected to the alarms 103
via a communication path 109. The second service representative
communicates with the first service representative 101 via a second
two-way radio 111. The service representatives must perform a
manual visual inspection to make sure that each alarm 103 is
functioning properly. One way to accomplish this is for the first
representative to walk to an alarm 103 to be tested and inform the
second representative to activate an alarm condition at alarm 103,
possibly activating other alarms outside the perception of the
first representative. Once the alarm 103 is activated, the first
representative must communicate his observations back to the second
service representative. To test the entire system, the process must
be repeated for each alarm 103 in the system.
The walk through test required at the installation and regular
maintenance of fire alarm systems is time consuming, costly and
potentially disruptive particularly if the alarm 103 has a sound
notification component. Further, because it is prone to human
error, the walk through test is unreliable. A system is needed that
requires less human involvement, less time to test alarm devices,
is less disruptive, and is more reliable.
SUMMARY OF INVENTION
A self-testing notification appliance includes a notification
emitter, a verification circuit, and a controller. The notification
emitter includes a visual notification (e.g., strobe) and may
optionally also include aural notification (e.g., speaker or horn).
The notification emitter may output visual notification based on a
control signal. The visual notification is indicative of an alarm
event. The verification circuit may include one or more
notification sensors to detect the visual notification and generate
a verification signal. The controller may initiate the test and/or
receive input to test the notification appliance (such as receiving
input from a remote central controller or from an input device,
such as a switch) on the notification appliance, as discussed in
more detail below. The controller may then send a control signal to
instruct the notification emitter to conduct a test, and receive
information indicating the result of the test, such as the
verification signal from the verification circuit.
In one application of a self-testing notification appliance, the
verification circuit may determine the brightness or intensity of
the light. For example, the notification appliance may operate the
strobe in an alarm mode (i.e., generating an output
brightness/intensity of the strobe that is the same or
approximately the same as the output brightness/intensity that is
required or rated for notification of an alarm event). The
verification circuit may then provide information on the brightness
or intensity of the light in order to determine whether the strobe,
during test operation, output brightness/intensity that is required
or rated for notification of an alarm event. If the
brightness/intensity of the strobe is less than that required or
rated for notification of an alarm event, the controller may adjust
the brightness and/or intensity of the strobe based on the
verification signal so that the output of the strobe is at least as
much as required for notification of an alarm event.
In one embodiment, the self-testing notification appliance may be
part of a network including a fire alarm control panel and a
plurality of additional self-testing notification appliances. The
self-testing notification appliances may be assigned addresses on
the network. The fire control panel may send control signals to the
notification appliance based on the network address. The fire
control panel may receive test information from the notification
appliance and compile that information, along with test information
from other self-testing notification appliances.
In one embodiment, the self-testing notification appliance is not
addressable. A fire alarm control panel may be networked with a
plurality of non-addressable notification appliances on a common
circuit. A control signal from the fire alarm control panel
controls all notification appliances on the common circuit to
output light. A verification circuit on the notification appliance
detects whether the light intensity is above a threshold level. If
the light intensity is not above a threshold level, the
notification appliance will interrupt a signal sent by the fire
alarm control panel. The interruption will indicate to the fire
alarm control panel that a failure has occurred.
The present invention is defined by the following claims, and
nothing in this section should be taken as a limitation on those
claims. The preferred embodiments will now be described with
reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an example of a process to assess if a
conventional fire alarm system is properly working.
FIG. 2 illustrates a notification system according to an
embodiment.
FIG. 3 illustrates a schematic diagram of the notification system
of FIG. 2 including an exemplary notification appliance.
FIG. 4 illustrates one implementation of a verification circuit of
the notification appliance.
FIG. 5 illustrates another implementation of a verification circuit
of the notification appliance.
FIG. 6 illustrates yet another implementation of a verification
circuit of the notification appliance.
FIG. 7 illustrates a testing procedure performed by the system
control panel.
FIG. 8 illustrates a testing procedure performed by the
notification appliance.
FIG. 9 illustrates an exploded view the notification appliance.
FIG. 10 illustrates a notification system including non-addressable
notification appliances.
DETAILED DESCRIPTION
The present embodiments relate to self-testing notification
appliances or devices. Notification appliances may include a visual
alarm (strobe) and may additionally include an audible alarm (horn
or speaker). A notification appliance is self-testing when it is
capable of performing a test through instruction from a controller
or control panel without requiring a person to be physically within
audible range or visual range of the notification appliance to
verify the proper operation of the appliance. This is accomplished
by including a verification circuit in the notification appliance
that is capable of detecting the visible or audible
notification.
The controller instructs the notification appliance to illuminate
an alarm, and a verification circuit detects the alarm. The
verification circuit detects the alarm by a sensor and circuitry
located in the appliance. The notification sensor could be a
photodetector capable of detecting a visual alarm. Alternatively,
the notification sensor may include both a photodetector capable of
detecting a visual alarm and a microphone capable of detecting an
audible alarm. The self-testing notification appliance may be
directly connected to a controller or control panel or it may be
connected to a network for communication with the controller or
control panel. The connection may be wired or wireless. The
self-testing notification appliance may be individually addressable
and communicate independently with the control panel or the
self-testing notification appliance may be wired along with a group
of notification appliances on a circuit (non-addressable).
A notification system is illustrated in FIG. 2. The system includes
a network 16, having alarm condition detectors D and alarm
notification appliances A. A system controller or fire alarm
control panel (FACP) 14 monitors the detectors D. Detectors D may
include, but are not limited to, fire detectors, smoke detectors,
radiation detectors, heat detectors, carbon monoxide detectors,
ozone detectors or other gas detectors. Detectors D automatically
provide an indication of an alarm condition to the system
controller 14. Although not shown, manual alarm triggers may also
provide an indication of an alarm condition to the system
controller 14. Manual alarm triggers include a pull device, push
button triggers, and glass break triggers.
As an alternative to the notification system illustrated in FIG. 2,
the detectors D and notification appliances A may communicate with
FACP 14 through separate circuits. The detectors D may have power
signal requirements and communication signal requirements much
different than those of notification appliances A. For example in
one embodiment, detectors D may require one-way communication,
while notification appliances A may require two-way communication.
In another example, notification appliances A may require more
power, and accordingly a heavier gauge power cable, than the
detectors D. In either of these examples, it would be advantageous
for the detectors D and notification appliances A to be networked
by separate circuits.
When an alarm condition is sensed, the system controller 14 signals
the alarm to the appropriate notification appliances through one or
more networks 16. Although other configurations are available, in
the network 16 shown, the notification appliances are coupled
across a pair of power lines 18 and 20 that also carry
communications between the system controller 14 and the detectors D
and notification appliances A. Network 16 carries two-way
communication between the system controller 14 and the notification
appliances A.
The communication signal can, for example, be multiplexed onto the
device's power line--this provides the added benefit that it saves
the cost of additional wiring to devices. See for example, U.S.
Pat. No. 6,426,697, incorporated by reference herein in its
entirety. Alternatively, the communication line to the device may
be separate from the power line. The communications channel may
comprise a wired link or a wireless link using, for example, radio,
an infrared link, or a fiber optic link.
Notification appliances A and detectors D are addressable on the
network 16. The system controller 14 may be configured to provide
addresses to the notification appliances A and detectors D. The
addresses may be non-duplicative, in which each notification
appliance A and detector D receives a unique addresses.
Alternatively, the addresses may be assigned in groups. The address
for each of the notification appliances A may be set by a signal
download from an external programming tool provided at system
controller 14 or by manually configuring switches located on or
internal to the device. A label may be affixed to the notification
appliance to indicate the address that has been assigned to that
notification appliance.
FIG. 3 is a schematic diagram of the system of FIG. 2. For
simplicity, the two-line network of FIG. 2 is shown with a single
line 16 which is used to logically represent a connection in
general which may be wired with any number of lines or may be a
wireless link. The control panel 14 includes user interface 51,
memory 55, microprocessor 53, and communicator 57.
Microprocessor 53 manages the control panel 14 and alarm system.
Microprocessor 53 receives commands from instructions stored in
memory 55 and receives commands from user interface 51. User
interface 51 is a keyboard or other input device configured to
allow a user or a computer to enter commands to the control panel
14. Microprocessor 53 may also receive commands from a removable
medium. Memory 55 may also store the testing procedure or testing
schedule performed by the control panel 14 in testing the
verification circuits and the notification appliances.
The control panel 14 may be embodied on a personal computer, and
the functions of the control panel may also be embodied on
software. The testing and verification process can be carried out
automatically by the control panel 14 or through instruction from
the user by way of the user interface 51. Control panel 14 may also
include a modem or network interface card configured to communicate
with an intranet computer network or with the Internet. The testing
schedule performed by the verification circuit could be downloaded
by control panel over the intranet computer network or the
internet.
Communicator 57 is configured to send and receive commands and/or
data from network 16. Communicator 57 includes a network interface
as well as the decoding circuitry and amplification circuitry
necessary for communication on network 16.
FIG. 3 further illustrates strobe device 30 as an example of a
notification appliance A. Strobe device 30 includes a controller
26, communicator or network interface 24, and verification circuit
28. Strobe device 30 includes strobe 22 which may be embodied as a
Xenon flashtube or light emitting diode (LED). The notification
appliance optionally includes memory 32 and indicator 34. Although
the implementation shown in FIG. 3 includes only strobe 22, the
notification emitter may additionally include audio devices or
sounders such as horns, bells, or speakers.
The light from the notification appliance provides a visual
notification to people in the vicinity of the notification
appliance. The sensory notification may be determined by
regulations for notifying of an alarm event. For example,
regulations dictate the intensity or brightness of the sensory
notification of a strobe.
Strobe device 30 connects to the network 16 via a communicator 24.
Communicator 24 is configured to send and receive commands and/or
data from network 16. Communicator 24 includes a network interface
as well as the decoding circuitry and amplification circuitry
necessary for communication on network 16. Controller 26 receives
commands from and sends data to the control panel 14 by way of
communicator 24.
Controller 26 may be embodied as a microcontroller, an integrated
circuit, or any hardwired logic. When commanded by controller 26, a
driving circuit supplies power and a trigger signal to illuminate
strobe 22. The driving circuit may include a chargeable member,
such as a high voltage capacitor, to supply power to strobe 22.
Memory 32 stores instructions for controller 26 and may be
configured to store a testing schedule, as addressed below.
The controller 26 may generate a control signal to send to the
strobe 22. The strobe 22 may receive the control signal and may
output light at the intensity/brightness the same as (or similar
to) the intensity/brightness as required by regulations for
notifying occupants of a premises of an alarm event. The controller
26 may generate the control signal sent to strobe 22 in response to
a command sent from control panel 14. In turn, the command sent
from the control panel may be generated in response to input to the
networked computer from the user or in response to a predetermined
schedule of testing stored in memory 55 of the control panel 14.
The controller 26 may also generate the control signal in response
to an instruction input from the user, such as an instruction
wirelessly communicated by the user or communicated via an input
panel on the strobe device 30. Or, the controller 26 may generate
the control signal based on a predefined testing schedule that may
be resident locally at the strobe device 30 in memory 32. The
verification circuit 28 receives commands from controller 26 to
detect the operation of the strobe 22. The command from the
controller 26 to verification circuit 28 may also include a test
duration signal. From the test duration signal, the verification
circuit 28 is configured to perform detection of strobe 22 for a
predetermined time period.
FIG. 4 illustrates a detailed view of the verification circuit 28,
including a notification sensor 527 and a threshold detector 529.
The threshold detector 529 is in communication with controller
26.
Notification sensor 527 includes a photodetector, such as a
photodiode. The photodiode is a light sensing device that is
configured to receive light from strobe 22, sense the light at
discrete frequencies or one or more frequency ranges, and output a
signal indicative of the amount of light sensed. The frequency
ranges may be selected such that the notification sensor senses all
types of visible light.
When the notification appliance additionally includes a horn or
speaker, notification sensor 527 may additionally includes a
microphone or other sound pressure level measurement device. The
microphone is configured to receive the output of the horn or
speaker and output a signal indicative of the sound received. The
verification circuit may also be configured with filters so that
the microphone outputs the signal only for input sounds
corresponding to a defined range of frequencies. Other types of
sensors may be used as long as the sensor is able to detect the
notification emitted by the appliance.
A reflector or shield may be used to prevent the notification
sensor 527 from falsely detecting light from sources other than
strobe 22. The other sources of light may cause interference to the
system and should be avoided. The other sources of light may
include ambient light from sunlight or lighting in the building.
Even though the intensity of the light emitted from strobe 22 will
normally be orders of magnitude greater than the intensity of
surrounding light, the reflector or shield will further minimize
the effects of surrounding light.
The threshold detector 529 receives the output of the notification
sensor 527 and functions as a comparator. Threshold detector 529
may include a variably set threshold value. The output of the
threshold detector 529 is sent to the controller 26. The sources of
light that may potentially cause interference will generally be low
enough in intensity during activation of the device that the
notification sensor 527 will output a value lower than the
threshold value of threshold detector 529.
In addition, ambient light will generally cause a constant level of
output from the notification sensor 527. Strobe 22, however, will
cause a sharp spike in the output of the notification sensor 527.
By setting the threshold value above the ambient light levels but
well below the typical spike caused by the strobe light, the
verification circuit avoids indicating false positives in the
testing procedure.
FIG. 5 illustrates another example of verification circuit 28. In
this example, verification circuit 28 includes a measurement
circuit 531 and notification sensor 527. Measurement circuit 531
receives the output of the notification sensor 527, converts the
signal to a scaled value, and sends a measurement signal including
the scaled value to the controller 26. The measurement circuit 531
may include an analog to digital converter (ADC) and a peak and
hold circuit to send, as the measurement signal, a digital
representation of the output of the notification sensor 527 to the
controller 26. Controller 26 may perform a threshold comparison to
determine if the output of the notification sensor 527 is in an
acceptable range as determined by software settings within the
controller 26. Alternatively, controller 26 may make no comparison
and simply send the data to the alarm panel for analysis there.
The signal from the verification circuit 28 to controller 26,
referred to as the verification signal, may include the threshold
signal or the measurement signal.
FIG. 6 illustrates yet another example of verification circuit 28.
In this example the function of measurement circuit 531 is
implemented by controller 26. The controller 26 receives the direct
output of the notification sensor 527.
In the examples of FIG. 5 and FIG. 6, the measurement signal may be
used to calibrate strobe 22. The level of the measurement signal as
determined by the measurement circuit 531 or by controller 26
indicates the intensity of the strobe 22. Over time, the intensity
of strobe 22 may deteriorate. Controller 26 is configured to
determine the level of intensity of strobe 22 based on the
measurement signal. The controller 26 may compare the level of
intensity of strobe 22 with a rated intensity stored in memory 32.
Based on this comparison, controller 26 may adjust the control
signal sent to the driving circuit of strobe 22 to increase or
decrease the output intensity or brightness of the light so that
the strobe 22 outputs light at approximately the rated intensity. A
system adapted to select the intensity of a strobe is shown and
described by U.S. Patent Application Publication No. US
2005/0128097, which is hereby incorporated by reference in its
entirety.
Likewise, in the case of a notification appliance with strobe 22
and a horn or speaker, the notification sensor 527 outputs a signal
indicative of the intensity of the sound. Measurement circuit 531
or controller 26 is configured to determine the level of intensity
of the sound. The controller 26 may compare the intensity of the
sound with a rated intensity stored in memory 32, and adjust the
control signal sent to the driving circuit accordingly. A system
adapted to select the intensity of a speaker is shown and described
by U.S. patent application No. US 2008/0219458, which is hereby
incorporated by reference in its entirety.
FIG. 7 illustrates the testing procedure performed at control panel
14. At block S101, the control panel 14 receives a command from a
user or from a predetermined testing schedule stored in memory 55.
Alternatively, the testing schedule may be stored in memory 32 at
the notification appliance 30. At block S103, the control panel 14
selects an addressed notification appliance to perform the test.
The control panel 14 may sequence the testing procedure among the
notification appliances or they may all be tested at the same time
or in groups. At block S105, the control panel 14 sends the testing
command to the first addressed notification appliance (or group of
notification appliances) in the testing schedule. At block S107,
the control panel 14 receives information back from the
notification appliance. The information may either be the test
data, at which point the control panel analyzes the data, or the
result of an analysis performed by the measurement circuit 531 and
controller 26.
At block S109, the control panel 14 logs the test result. At block
S111, the control panel 14 checks the testing schedule to determine
if tests of additional notification appliances are to be run. If no
additional tests are to be run, the control panel 14, at block S113
reports the cumulative test results. The test results may be
displayed to the user via user interface 31, stored in memory 55,
or transmitted to an external device, such as a printer.
Additionally, the test results or the list of test results may be
emailed or otherwise electronically transmitted to a user or
customer. If additional tests are to be run, the control panel
returns to block S 103 and repeats the procedure until no
additional tests are remaining.
FIG. 8 illustrates the testing procedure performed by controller 26
in the notification appliance. At block S201, controller 26 decodes
the testing command from the control panel 14. At block S203, the
controller 26 initiates the notification from either strobe 22 or
an audible device or both if so equipped. At block S205, the
controller 26 reads the test data from the verification circuit 28.
Optionally, the controller 26 may analyze the test data, as
indicated by block S207. At block S209, information is sent to the
control panel 14. The information is the test data, if S207 is
omitted, and the information is the analysis results, if S207 is
not omitted.
In an embodiment in which controller 26 analyzes the test data, an
indicator 34, as shown in FIG. 3 indicates the result of the
analysis of the test data. The indicator receives an indicator
signal from controller 26. For example, an unlit light emitting
diode (LED) may indicate that the most recent test was successful
and a lit LED may indicate that the most recent test was
unsuccessful.
FIG. 9 illustrates an exploded view of a notification appliance 800
including a strobe as light emitting device 801, a reflector 803, a
housing 813, and a circuit 815. Light emitting device 801 may be a
Xenon flashtube, a strobe light, or a light emitting diode (LED).
Circuit 815 includes a driving circuit, a verification circuit, and
a controller similar to previously discussed embodiments. The
driving circuit may be isolated from the verification circuit to
reduce false test results.
The verification circuit portion of circuit 815 includes photodiode
817 Photodiode 817 may be implemented as any type of photodetector.
Examples of suitable photodetectors include optical detectors,
photoresistors, photovoltaic, phototransistors, charge-coupled
devices (CCD), or reverse biased LEDs. Light pipes may be used to
further reduce false testing by providing additional shielding or
preferred placement of the photodetector relative to the strobe
and/or shield.
The driving circuit portion of circuit 815 includes a chargeable
member, which may be implemented as a high voltage capacitor.
Exemplary driving circuits are shown and described by U.S. Patent
Application Publication No. US 2007/0263279, which is hereby
incorporated by reference in its entirety.
Housing 813 is formed to encase the notification appliance 800.
Housing 813 may be formed of plastic, glass, resin, metal, or any
suitable material. Materials that are resistant to heat may be
advantageous or required by applicable regulations.
Reflector 803 is mounted between the light emitting device 801 and
the verification circuit for the purposes of focusing the emitted
light into the room at areas that enhance notification, while, at
the same time, allowing light from the light emitting device 801 to
reach photodiode 817. Further, the reflector reduces the ambient
light that reaches the photodiode 817. One exemplary design
includes an angled reflective sheet including an opening 809. The
angled sheet forms a first plane 805 and second plane 807.
Reflector 803 may be a polished metal, such as stainless steel.
Reflector 803 may be formed from plastic, paper, resin, or
cardboard coated or painted on one or both sides with a reflective
paint or other substance. As discussed above, ambient light caused
by sunlight or light fixtures may be present in the location where
notification appliance 800 has been installed. Reflector 803
reduces the effects of ambient light.
Reflector 803 further includes holes 811 to pass the leads of the
light emitting device 801 to the driving portion of circuit 815.
Opening 809 allows a controlled portion of light to pass through
the reflector 803 to be detected by photodiode 817. In this manner,
the amount of ambient light reaching the photodetector 817 is
reduced.
Besides ambient light, interference may, in some circumstances, be
caused by electromagnetic fields (EMF). The driving circuit
utilizes high voltages, and the resulting EMF may cause voltage
disturbances in the output of the photodetector 817. In this case,
light pipes may be utilized to further distance and isolate the
photodetector 817 from the driving circuit portion of circuit 815.
Alternatively, or in addition to light pipes, digital logic,
filtering, or an analog circuit the false positives caused by the
EMF can be distinguished from the intended output signal from a
sensory notification from the notification emitter.
Notification appliance 800 of FIG. 9 may be non-addressable. FIG.
10 illustrates an exemplary notification system implementing a
non-addressable notification appliance 930. One or more
non-addressable notification appliances may be connected to fire
alarm control panel 914 on a circuit. The non-addressable
notification appliance includes a strobe 922 and a verification
circuit 928. The strobe 922 of the non-addressable notification
appliance emits light from power supplied by the fire alarm control
panel. The fire alarm control panel 914 may be implemented in a
similar manner and using similar components as fire alarm control
panel 14, shown in FIG. 3.
Non-addressable notification appliances do not necessarily include
a controller. The fire alarm control panel 914 controls all
notification appliances on the circuit together, and there is not
two-way communication between the fire alarm control panel and an
individual notification appliance. Fire alarm control panel 914 is
coupled to non-addressable notification appliance 930 via a single
pair of wires that provides power to the notification device.
Alternatively, two or more non-addressable notification devices may
be coupled to the fire alarm control panel 914 using a single pair
of wires.
A control signal is multiplexed onto the power signal. A strobe 922
outputs an amount of light based on the control signal. A
verification circuit 928 is activated based on the control signal.
As discussed in the previous embodiments, the verification circuit
928 includes a photodetector. When the control signal instructs the
strobe 922 to output an amount of light and the photodetector
detects that the intensity of the light is below the threshold, the
verification circuit will interrupt the power signal. The
interruption appears as an open circuit to the fire control panel
914.
In one embodiment, when two or more non-addressable notification
appliances 930 are coupled to the fire alarm control panel 914
using a common notification appliance circuit, the fire control
panel 914 cannot distinguish which appliance caused the open
circuit. The open circuit may indicate the failure of one or more
strobes on the common notification appliance circuit.
Alternatively, the non-addressable notification appliances 930 may
be coupled to the fire alarm control panel 914 on individual
circuits.
The fire alarm control panel 914 may log the failure of the one or
more strobes in a memory. Further, the fire alarm control panel 914
may print, display, or email the failure of the one or more
strobes.
Additionally, the features described above with respect to
addressable notification appliances may be applied to
non-addressable notification appliance where functions performed by
the controller of the addressable notification appliance are
performed by the fire alarm control panel 914.
Although specific embodiments of the invention have been described
and illustrated, the invention is not to be limited to the specific
forms or arrangements of parts so described and illustrated. The
scope of the invention is to be defined by the claims appended
hereto and their equivalents. It is intended that the foregoing
detailed description be understood as an illustration of selected
forms that the invention can take and not as a definition of the
invention. It is only the following claims, including all
equivalents that are intended to define the scope of this
invention.
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